The present invention relates to one way valves and particularly flapper type valves which are employed in a fuel tank filler tube for accommodating insertion of a refueling nozzle and providing for closure and sealing of the filler tube upon removal of the nozzle at the completion of refueling.
In the current production of truck and passenger vehicles, mandated fuel vapor emission requirements necessitate the sealing of the fuel tank to prevent escape of fuel vapor to the atmosphere. Present design practice is to provide a one-way valve in the fuel tank filler tube and located downstream of an aperture and seal provided for sealing about a refueling nozzle upon insertion of same in the filler tube. This arrangement thus prevents escape of fuel vapor to the atmosphere from the filler tube both during refueling and upon removal of the refueling nozzle.
Presently, a greater number of motor vehicle fuel tanks are formed of non-metallic material; however, metal fuel tanks are still employed on production vehicles and consequently provision must be made for providing a check valve in the filler tube for both metal and plastic fuel tanks. Typically, the upper section of the filler tube, which is attachable to the vehicle structure in light trucks and passenger cars, is formed of flexible material with a tubular flanged fitting or “spud”, as it is sometimes referred to, is attached to the downstream end thereof. The spud is secured and sealed to the tank typically by weldment.
Furthermore, the one-way valve must accommodate insertion of a siphon hose in the filler tube such that the hose can pass through the valve and into the tank with the lower end of the hose contacting the bottom of the fuel tank. Thus, it has been found convenient to have the downstream end of the one-way valve extend into the fuel tank and to have oriented apertures in the side of the valve to direct the siphon hose toward the bottom of the tank. This has required proper rotational orientation of the valve in the tank spud and the spud on the tank in order to provide for directing the siphon hose to the bottom of the tank.
In addition, it has been desired to provide a relatively low cost design for attaching the flapper valve element to the valve body and to provide for biasing the flapper to the closed position and self alignment to ensure automatic closing upon removal of a fuel filler nozzle or siphon hose.
Heretofore, it has proven difficult in manufacturing and assembly of such a valve to provide for biasing the flapper closed in a manner which was cost effective in high volume production and easy to assemble. Furthermore, it has been found relatively costly and difficult to provide a pivot or hinge mechanism for pivoting the flapper and to attach the flapper to the valve body in a manner which ensures positive closing self alignment and sealing of the flapper to prevent emission of fuel vapor. Thus, it has been desired to provide a simple, easy-to-assemble and relatively low cost one-way flapper valve for a fuel tank filler tube which readily receives a siphon hose and which is orientable in the filler hose to direct the siphon hose toward the bottom of the tank.
It has further been desired to provide a fuel tank filler tube valve which can accommodate attachment to either a metal or plastic tank spud and which has a minimum number of parts to simplify assembly and minimize manufacturing costs.